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Scientists to study possible link between wells, Greeley earthquake

By Sharon DunnGreeley Tribune

Posted:
06/09/2014 12:01:00 AM MDT

Updated:
06/09/2014 09:32:01 AM MDT

A red flag marks the seismic monitor buried in the ground as Jenny Nakai, a graduate student in seismology from University of Colorado at Boulder, begins checking one of the instruments above near the intersection of Weld County Road 64 south of Lucerne, Colo. (Joshua Polson, The Greeley Tribune)

The answer to Greeley's first earthquake in at least 40 years may be sitting 10,000 feet below the surface in a deep-water trash can that might be overfilling.

The oil and gas boom has put added stress on the industry's wastewater injection wells that cut 2 miles below the surface.

Still, some say the answer may be as simple as water management.

Wastewater injection wells — which take in produced water from fracking jobs — may now go under increasing scrutiny in Colorado, as scientists have found connections between them and a spate of small earthquakes across the country in recent years.

Still, most injection wells are not linked to any earthquakes; it's only a tiny fraction of injection wells that have specifically been cited as the cause of a minor quake.

Anne Sheehan, professor of geophysics at the University of Colorado Boulder, holds one of the seismographs, similar to ones her team from the university have set up around the epicenter of the earthquake in Greeley, Colo. (Joshua Polson, The Greeley Tribune)

Researchers from the University of Colorado at Boulder put out seismographic equipment throughout Weld County last week, hoping to cull the earth's secrets into a database of answers. If injection wells are found to be the common denominator in further quake activity, they'll capture it.

But in the absence of answers, some would say solutions are not difficult.

"There are ways to fix this," said Ken Carlson, an associate professor of civil and environmental engineering at Colorado State University.

"This is sort of a byproduct of too much water being disposed of, but it's not like we should shut it down," Carlson said. " It just means we need to improve our water management. ... Just drill new wells and increase recycling."

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Injection wells have long been tools for oil and gas companies to dispose of wastewater. The water is pumped 2 miles beneath the surface into porous rock, through which the water disperses — allowing more water to be pumped in.

The process is regulated by the federal Environmental Protection Agency and state oil and gas regulators.

Operators must adhere to disposing of water at tested rates and volumes, so as not to overwhelm the well, and are subjected to annual inspection and well integrity testing every five years, state officials say.

For Anadarko Petroleum Corp., which is working to manage its water resources by using municipal effluents, recycling and piping water into sites rather than trucking, officials say they may be coming close to a "limit" on its injections wells.

"The wells are definitely a cause of concern with induced seismicity," said Korby Bracken, environmental health and safety manager for Anadarko. "We think they'll continue to be used, but it's something we're studying quite a bit."

Anadarko has a permit pending for an injection well and has three in Colorado that are running at capacity.

"That being said, we're looking at other and alternative ways to recycle the fluids that come from the well bore," Bracken said. "So we don't have to rely as much on those saltwater injection wells."